/*
 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

#ifndef ZSTDv05_H
#define ZSTDv05_H

#if defined(__cplusplus)
extern "C" {
#endif

/*-*************************************
 *  Dependencies
 ***************************************/
#include <stddef.h> /* size_t */

#include "mem.h" /* U64, U32 */

/* *************************************
 *  Simple functions
 ***************************************/
/*! ZSTDv05_decompress() :
    `compressedSize` : is the _exact_ size of the compressed blob, otherwise decompression will fail.
    `dstCapacity` must be large enough, equal or larger than originalSize.
    @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
              or an errorCode if it fails (which can be tested using ZSTDv05_isError()) */
size_t ZSTDv05_decompress(void* dst, size_t dstCapacity, const void* src, size_t compressedSize);

/**
ZSTDv05_findFrameSizeInfoLegacy() : get the source length and decompressed bound of a ZSTD frame compliant with v0.5.x
format srcSize : The size of the 'src' buffer, at least as large as the frame pointed to by 'src' cSize (output
parameter)  : the number of bytes that would be read to decompress this frame or an error code if it fails (which can be
tested using ZSTDv01_isError()) dBound (output parameter) : an upper-bound for the decompressed size of the data in the
frame or ZSTD_CONTENTSIZE_ERROR if an error occurs

   note : assumes `cSize` and `dBound` are _not_ NULL.
*/
void ZSTDv05_findFrameSizeInfoLegacy(const void* src, size_t srcSize, size_t* cSize, unsigned long long* dBound);

/* *************************************
 *  Helper functions
 ***************************************/
/* Error Management */
unsigned ZSTDv05_isError(size_t code);         /*!< tells if a `size_t` function result is an error code */
const char* ZSTDv05_getErrorName(size_t code); /*!< provides readable string for an error code */

/* *************************************
 *  Explicit memory management
 ***************************************/
/** Decompression context */
typedef struct ZSTDv05_DCtx_s ZSTDv05_DCtx;
ZSTDv05_DCtx* ZSTDv05_createDCtx(void);
size_t ZSTDv05_freeDCtx(ZSTDv05_DCtx* dctx); /*!< @return : errorCode */

/** ZSTDv05_decompressDCtx() :
 *   Same as ZSTDv05_decompress(), but requires an already allocated ZSTDv05_DCtx (see ZSTDv05_createDCtx()) */
size_t ZSTDv05_decompressDCtx(ZSTDv05_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);

/*-***********************
 *  Simple Dictionary API
 *************************/
/*! ZSTDv05_decompress_usingDict() :
 *   Decompression using a pre-defined Dictionary content (see dictBuilder).
 *   Dictionary must be identical to the one used during compression, otherwise regenerated data will be corrupted.
 *   Note : dict can be NULL, in which case, it's equivalent to ZSTDv05_decompressDCtx() */
size_t ZSTDv05_decompress_usingDict(ZSTDv05_DCtx* dctx,
                                    void* dst,
                                    size_t dstCapacity,
                                    const void* src,
                                    size_t srcSize,
                                    const void* dict,
                                    size_t dictSize);

/*-************************
 *  Advanced Streaming API
 ***************************/
typedef enum {
    ZSTDv05_fast,
    ZSTDv05_greedy,
    ZSTDv05_lazy,
    ZSTDv05_lazy2,
    ZSTDv05_btlazy2,
    ZSTDv05_opt,
    ZSTDv05_btopt
} ZSTDv05_strategy;
typedef struct {
    U64 srcSize;
    U32 windowLog; /* the only useful information to retrieve */
    U32 contentLog;
    U32 hashLog;
    U32 searchLog;
    U32 searchLength;
    U32 targetLength;
    ZSTDv05_strategy strategy;
} ZSTDv05_parameters;
size_t ZSTDv05_getFrameParams(ZSTDv05_parameters* params, const void* src, size_t srcSize);

size_t ZSTDv05_decompressBegin_usingDict(ZSTDv05_DCtx* dctx, const void* dict, size_t dictSize);
void ZSTDv05_copyDCtx(ZSTDv05_DCtx* dstDCtx, const ZSTDv05_DCtx* srcDCtx);
size_t ZSTDv05_nextSrcSizeToDecompress(ZSTDv05_DCtx* dctx);
size_t ZSTDv05_decompressContinue(ZSTDv05_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);

/*-***********************
 *  ZBUFF API
 *************************/
typedef struct ZBUFFv05_DCtx_s ZBUFFv05_DCtx;
ZBUFFv05_DCtx* ZBUFFv05_createDCtx(void);
size_t ZBUFFv05_freeDCtx(ZBUFFv05_DCtx* dctx);

size_t ZBUFFv05_decompressInit(ZBUFFv05_DCtx* dctx);
size_t ZBUFFv05_decompressInitDictionary(ZBUFFv05_DCtx* dctx, const void* dict, size_t dictSize);

size_t ZBUFFv05_decompressContinue(ZBUFFv05_DCtx* dctx,
                                   void* dst,
                                   size_t* dstCapacityPtr,
                                   const void* src,
                                   size_t* srcSizePtr);

/*-***************************************************************************
 *  Streaming decompression
 *
 *  A ZBUFFv05_DCtx object is required to track streaming operations.
 *  Use ZBUFFv05_createDCtx() and ZBUFFv05_freeDCtx() to create/release resources.
 *  Use ZBUFFv05_decompressInit() to start a new decompression operation,
 *   or ZBUFFv05_decompressInitDictionary() if decompression requires a dictionary.
 *  Note that ZBUFFv05_DCtx objects can be reused multiple times.
 *
 *  Use ZBUFFv05_decompressContinue() repetitively to consume your input.
 *  *srcSizePtr and *dstCapacityPtr can be any size.
 *  The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
 *  Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
 *  The content of @dst will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it
 * matters or change @dst.
 *  @return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to help latency)
 *            or 0 when a frame is completely decoded
 *            or an error code, which can be tested using ZBUFFv05_isError().
 *
 *  Hint : recommended buffer sizes (not compulsory) : ZBUFFv05_recommendedDInSize() / ZBUFFv05_recommendedDOutSize()
 *  output : ZBUFFv05_recommendedDOutSize==128 KB block size is the internal unit, it ensures it's always possible to
 * write a full block when decoded. input  : ZBUFFv05_recommendedDInSize==128Kb+3; just follow indications from
 * ZBUFFv05_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
 * *******************************************************************************/

/* *************************************
 *  Tool functions
 ***************************************/
unsigned ZBUFFv05_isError(size_t errorCode);
const char* ZBUFFv05_getErrorName(size_t errorCode);

/** Functions below provide recommended buffer sizes for Compression or Decompression operations.
 *   These sizes are just hints, and tend to offer better latency */
size_t ZBUFFv05_recommendedDInSize(void);
size_t ZBUFFv05_recommendedDOutSize(void);

/*-*************************************
 *  Constants
 ***************************************/
#define ZSTDv05_MAGICNUMBER 0xFD2FB525 /* v0.5 */

#if defined(__cplusplus)
}
#endif

#endif /* ZSTDv0505_H */
